INFUSORIA. 163 



(fig. 35). In some cases the Vorticella assumes the 

 form of a Podoph'rya (fig. 40), the surface becoming 

 covered with tentacle-like processes. This Podophrya 

 was formerly considered a distinct species. 



Vaginic'ola crystal'lina (fig. 33) is contained in a 

 crystalline tube, from which the body can be pro- 

 truded. The body is of variable form, presenting 

 when fully extended a trumpet shape. The cilia exist 

 at the anterior end, and extend down a lateral fissure 

 as in Vorticella. It is found attached to Confervas in 

 the water of ponds and bog-pools. 



Stentor polymor'phus (fig. 38) is a very beautiful 

 trumpet-shaped infusorium, the body being covered 

 with spiral rows of cilia. The rim is furnished with 

 stouter cilia, its margins at the notch being spirally 

 turned inwards. This infusorium is often found in 

 little groups attached to a gelatinous mass (fig. 38 c) ; 

 and it is met with also in a free or unattached state. 



COLEP'INA. Coleps hiatus (fig. 32) has a barrel- 

 shaped carapace, transversely and longitudinally fur- 

 rowed, the furrows being occupied by cilia. It has 

 two or three spines behind, and ten or twelve at the 

 front end of the carapace. It is common among 

 Confervse, and is very voracious, feeding upon dead 

 Entomostraca, &c. ; and if disturbed, at its meal by 

 moving the cover, it will soon return and resume 

 feeding as before. 



Examination. The Infusoria must be examined 

 during life ; for they are so altered by preservative 

 liquids that they cannot be well preserved. The 

 shells of those that are provided with them may be 

 kept simply dried upon a slide, and in this way a few 

 will retain their form, and the cilia of all may be more 

 easily distinguished ; the vacuoles may also then be 

 seen very distinctly. When they are confined in a 

 small quantity of water and are about to die, a curious 

 phenomenon may be observed in them, a number of 

 oil-like sarcodic globules exuding from the body, and 



